As if almost on queue, the coldest air of the season will arrive on the 2nd and 3rd (Friday & Saturday) days of the official start to fall.  Central, Eastern Ontario and Quebec will feel its effects first (with colder temperatures) on Friday before the cooling trend reaches S. Ont with less impact.  Temperatures will be somewhere between 17 – 19c with no humidity which is a big change from the relatively above average September we’ve experienced (except for the odd cooler day).

Here is a look from the GFS model for Friday afternoon:friday-gfs

I don’t expect the below normal temperatures will stick around for long, as the GFS model has things above average (above 18c) come the middle of next week possibly extending towards Thanksgiving weekend.  The more reliable Euro model was predicting a more seasonal outlook for the first couple weeks of October.  Given the strength of the heat this summer, I doubt it will give up so easily and flipping the switch will take sometime.  I suspect October may end up being pretty close to average.

Where did that Hurricane go?

Well the US Eastern seaboard can breath a sigh of relief as tropical storm Karl (actually just a depression at this time) that was targeting the area will make an abrupt northeast turn and head out to sea thanks to the placement of the jet stream, with a high pressure in the South Eastern US that develops later this week, as well as the High pressure coming down from the north through Ontario on Friday.  Unfortunately it puts Bermuda very close in it’s path, luckily the storm looks to have not gained enough strength when it skims Bermuda,so damage should be limited:hurricane

There was another Tropical storm (Lisa) behind Karl that will also make an abrupt turn again avoiding interaction with North America.  So far things have been lucky on the coast